Ball-and-stick model of the diamminesilver(I) cation, [Ag(NH3)2]+
Photograph taken by NASA's Voyager 2 in 1989
Ball-and-stick model of the tetraamminediaquacopper(II) cation, [Cu(NH3)4(H2O)2](2+)
Jabir ibn Hayyan
Galileo Galilei
This high-pressure reactor was built in 1921 by BASF in Ludwigshafen and was re-erected on the premises of the University of Karlsruhe in Germany.
Urbain Le Verrier
A train carrying Anhydrous Ammonia.
A size comparison of Neptune and Earth
Liquid ammonia bottle
Combined colour and near-infrared image of Neptune, showing bands of methane in its atmosphere, and four of its moons, Proteus, Larissa, Galatea, and Despina
Household ammonia
Bands of high-altitude clouds cast shadows on Neptune's lower cloud deck.
Ammoniacal Gas Engine Streetcar in New Orleans drawn by Alfred Waud in 1871.
The Great Dark Spot (top), Scooter (middle white cloud), and the Small Dark Spot (bottom), with contrast exaggerated.
The X-15 aircraft used ammonia as one component fuel of its rocket engine
Four images taken a few hours apart with the NASA/ESA Hubble Space Telescope Wide Field Camera 3
Anti-meth sign on tank of anhydrous ammonia, Otley, Iowa. Anhydrous ammonia is a common farm fertilizer that is also a critical ingredient in making methamphetamine. In 2005, Iowa used grant money to give out thousands of locks to prevent criminals from getting into the tanks.
Neptune (red arc) completes one orbit around the Sun (centre) for every 164.79 orbits of Earth. The light blue object represents Uranus.
The world's longest ammonia pipeline (roughly 2400 km long), running from the TogliattiAzot plant in Russia to Odessa in Ukraine
A diagram showing the major orbital resonances in the Kuiper belt caused by Neptune: the highlighted regions are the 2:3 resonance (plutinos), the nonresonant "classical belt" (cubewanos), and the 1:2 resonance (twotinos).
Hydrochloric acid sample releasing HCl fumes, which are reacting with ammonia fumes to produce a white smoke of ammonium chloride.
A simulation showing the outer planets and Kuiper belt: a) before Jupiter and Saturn reached a 2:1 resonance; b) after inward scattering of Kuiper belt objects following the orbital shift of Neptune; c) after ejection of scattered Kuiper belt bodies by Jupiter
Production trend of ammonia between 1947 and 2007
Natural-colour view of Neptune with Proteus (top), Larissa (lower right), and Despina (left), from the Hubble Space Telescope
Main symptoms of hyperammonemia (ammonia reaching toxic concentrations).
Neptune's moon Proteus
Ammonia occurs in the atmospheres of the outer giant planets such as Jupiter (0.026% ammonia), Saturn (0.012% ammonia), and in the atmospheres and ices of Uranus and Neptune.
A composite Hubble image showing Hippocamp with other previously discovered inner moons in Neptune's ring system
Neptune's rings
In 2018, the European Southern Observatory developed unique laser-based methods to get clear and high-resolution images of Neptune from the surface of Earth.
A Voyager 2 mosaic of Triton
The appearance of a Northern Great Dark Spot in 2018 is evidence of a huge storm brewing.<ref>{{cite web |title=A storm is coming |url= | |access-date=19 February 2019 |language=en |archive-url= |archive-date=20 February 2019 |url-status=live }}</ref>
The Northern Great Dark Spot and a smaller companion storm imaged by Hubble in 2020<ref>{{cite web|url=|title=Dark Storm on Neptune Reverses Direction, Possibly Shedding Fragment|author1=Michael H. Wong|author2=Amy Simon|publisher=Hubblesite|date=15 December 2020|access-date=25 December 2020|archive-date=25 December 2020|archive-url=|url-status=live}}</ref>
The Great Dark Spot, as imaged by Voyager 2
Neptune's shrinking vortex<ref>{{cite web|title=Neptune's shrinking vortex|url=||access-date=19 February 2018|archive-url=|archive-date=19 February 2018|url-status=live}}</ref>

Like Jupiter and Saturn, Neptune's atmosphere is composed primarily of hydrogen and helium, along with traces of hydrocarbons and possibly nitrogen, though it contains a higher proportion of "ices" such as water, ammonia and methane.

- Neptune

Ammonia is also found throughout the Solar System on Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto, among other places: on smaller, icy bodies such as Pluto, ammonia can act as a geologically important antifreeze, as a mixture of water and ammonia can have a melting point as low as 173 K if the ammonia concentration is high enough and thus allow such bodies to retain internal oceans and active geology at a far lower temperature than would be possible with water alone.

- Ammonia
Ball-and-stick model of the diamminesilver(I) cation, [Ag(NH3)2]+

4 related topics


Full disk view in natural colour, taken by the Hubble Space Telescope in April 2014


Fifth planet from the Sun and the largest in the Solar System.

Fifth planet from the Sun and the largest in the Solar System.

Full disk view in natural colour, taken by the Hubble Space Telescope in April 2014
Jupiter's diameter is one order of magnitude smaller (×0.10045) than that of the Sun, and one order of magnitude larger (×10.9733) than that of Earth. The Great Red Spot is roughly the same size as Earth.
Diagram of Jupiter, its interior, surface features, rings, and inner moons.
Time-lapse sequence from the approach of Voyager 1, showing the motion of atmospheric bands and circulation of the Great Red Spot. Recorded over 32 days with one photograph taken every 10 hours (once per Jovian day). See [[:File:Jupiter from Voyager 1 PIA02855 max quality.ogv|full size video]].
Close up of the Great Red Spot imaged by the Juno spacecraft in April 2018
The Great Red Spot is decreasing in size (May 15, 2014)
Jupiter (red) completes one orbit of the Sun (centre) for every 11.86 orbits by Earth (blue)
A rotation time-lapse of Jupiter over 3 hours
Model in the Almagest of the longitudinal motion of Jupiter (☉) relative to Earth (🜨)
Galileo Galilei, discoverer of the four largest moons of Jupiter, now known as Galilean moons
Infrared image of Jupiter taken by ESO's Very Large Telescope
Jupiter as seen by the space probe Cassini
A photograph of Jupiter taken by the Juno spacecraft, at the end of a close flyby
(September 2018)
Jupiter, as seen by the Juno spacecraft
(February 12, 2019)
The rings of Jupiter
Diagram showing the Trojan asteroids in Jupiter's orbit, as well as the main asteroid belt
Hubble image taken on July 23, 2009, showing a blemish about 5000 miles long left by the 2009 Jupiter impact event.
Jupiter, woodcut from a 1550 edition of Guido Bonatti's Liber Astronomiae
Infrared view of Jupiter, imaged by the Gemini North telescope in Hawaiʻi on January 11, 2017
Jupiter imaged in visible light by the Hubble Space Telescope on January 11, 2017
Ultraviolet view of Jupiter, imaged by Hubble on January 11, 2017<ref>{{cite web|title=By Jove! Jupiter Shows Its Stripes and Colors|publisher=National Science Foundation|website=NOIRLab|date=May 11, 2021|url=|access-date=June 17, 2021}}</ref>
This image of Jupiter and Europa, taken by Hubble on 25 August 2020, was captured when the planet was 653 million kilometres from Earth.<ref>{{cite web|title=Hubble Finds Evidence of Persistent Water Vapour Atmosphere on Europa|website=ESA Hubble|publisher=European Space Agency|date=October 14, 2021|url=|access-date=October 26, 2021}}</ref>

The atmosphere contains trace amounts of methane, water vapour, ammonia, and silicon-based compounds.

Based on spectroscopy, Saturn is thought to be similar in composition to Jupiter, but the other giant planets Uranus and Neptune have relatively less hydrogen and helium and relatively more of the next most common elements, including oxygen, carbon, nitrogen, and sulfur.

Photograph of Uranus in true colour (by Voyager 2 in 1986)


Seventh planet from the Sun.

Seventh planet from the Sun.

Photograph of Uranus in true colour (by Voyager 2 in 1986)
Simulated Earth view of Uranus from 1986 to 2030, from southern summer solstice in 1986 to equinox in 2007 and northern summer solstice in 2028.
Size comparison of Earth and Uranus
Diagram of the interior of Uranus
Uranus's atmosphere taken during the Outer Planet Atmosphere Legacy (OPAL) program.
Aurorae on Uranus taken by the Space Telescope Imaging Spectrograph (STIS) installed on Hubble.
The magnetic field of Uranus
(animated; 25 March 2020)
The first dark spot observed on Uranus. Image obtained by the HST ACS in 2006.
Uranus in 2005. Rings, southern collar and a bright cloud in the northern hemisphere are visible (HST ACS image).
Major moons of Uranus in order of increasing distance (left to right), at their proper relative sizes and albedos (collage of Voyager 2 photographs)
Uranus's aurorae against its equatorial rings, imaged by the Hubble telescope. Unlike the aurorae of Earth and Jupiter, those of Uranus are not in line with its poles, due to its lopsided magnetic field.
Crescent Uranus as imaged by Voyager 2 while en route to Neptune

Uranus is similar in composition to Neptune, and both have bulk chemical compositions which differ from that of the larger gas giants Jupiter and Saturn.

Uranus's atmosphere is similar to Jupiter's and Saturn's in its primary composition of hydrogen and helium, but it contains more "ices" such as water, ammonia, and methane, along with traces of other hydrocarbons.

The Solar System's four giant planets against the Sun, to scale

Giant planet

The giant planets constitute a diverse type of planet much larger than Earth.

The giant planets constitute a diverse type of planet much larger than Earth.

The Solar System's four giant planets against the Sun, to scale
Relative masses of the giant planets of the outer Solar System
These cut-aways illustrate interior models of the giant planets. Jupiter is shown with a rocky core overlaid by a deep layer of metallic hydrogen.
Saturn's north polar vortex
An artist's conception of 79 Ceti b, the first extrasolar giant planet found with a minimum mass less than Saturn.
Comparison of sizes of planets of a given mass with different compositions

There are four known giant planets in the Solar System: Jupiter, Saturn, Uranus and Neptune.

The principal components are hydrogen and helium in the case of Jupiter and Saturn, and water, ammonia and methane in the case of Uranus and Neptune.

Pictured in natural color approaching equinox, photographed by Cassini in July 2008; the dot in the bottom left corner is Titan


Sixth planet from the Sun and the second-largest in the Solar System, after Jupiter.

Sixth planet from the Sun and the second-largest in the Solar System, after Jupiter.

Pictured in natural color approaching equinox, photographed by Cassini in July 2008; the dot in the bottom left corner is Titan
The symbol for Saturn in late Classical (4th & 5th c.) and medieval Byzantine (11th c.) manuscripts, derives from (kappa-rho).
Composite image comparing the sizes of Saturn and Earth
Diagram of Saturn, to scale
Methane bands circle Saturn. The moon Dione hangs below the rings to the right.
A global storm girdles the planet in 2011. The storm passes around the planet, such that the storm's head (bright area) passes its tail.
Saturn and rings as viewed by the Cassini spacecraft (28 October 2016)
A montage of Saturn and its principal moons (Dione, Tethys, Mimas, Enceladus, Rhea and Titan; Iapetus not shown). This image was created from photographs taken in November 1980 by the Voyager 1 spacecraft.
Possible beginning of a new moon (white dot) of Saturn (image taken by Cassini on 15 April 2013)
Galileo Galilei observed the rings of Saturn in 1610, but was unable to determine what they were
Robert Hooke noted the shadows (a and b) cast by both the globe and the rings on each other in this drawing of Saturn in 1666.
Pioneer 11 image of Saturn
At Enceladus's south pole geysers spray water from many locations along the tiger stripes.
Amateur telescopic view of Saturn
Simulated appearance of Saturn as seen from Earth (at opposition) during an orbit of Saturn, 2001–2029
Saturn eclipses the Sun, as seen from Cassini. The rings are visible, including the F Ring.
orientation of its rings
HST Saturn portrait from 20 June 2019
Farewell to Saturn and moons (Enceladus, Epimetheus, Janus, Mimas, Pandora and Prometheus), by Cassini (21 November 2017).

Saturn has a pale yellow hue due to ammonia crystals in its upper atmosphere.

Wind speeds on Saturn can reach 1800 km/h, higher than on Jupiter but not as high as on Neptune.